Composition for etching

ABSTRACT

The disclosure is related to a composition for etching, a method for manufacturing the composition, and a method for fabricating a semiconductor using the same. The composition may include a first inorganic acid, at least one of silane inorganic acid salts produced by reaction between a second inorganic acid and a silane compound, and a solvent. The second inorganic acid may be at least one selected from the group consisting of a sulfuric acid, a fuming sulfuric acid, a nitric acid, a phosphoric acid, and a combination thereof.

CROSS REFERENCE TO PRIOR APPLICATIONS

The present application is continuation application of U.S. patentapplication Ser. No. 14/797,050 (filed on Jul. 10, 2015), now issued asU.S. Pat. No. 9,868,902, which claims priority under 35 U.S.C. § 119 toKorean Patent Application Nos. 10-2014-0090660 (filed on Jul. 17, 2014),10-2014-0090661 (filed on Jul. 17, 2014), 10-2014-0090662 (filed on Jul.17, 2014), 10-2014-0090663 (filed on Jul. 17, 2014), and 10-2015-0078400(filed on Jun. 3, 2015).

BACKGROUND

The present disclosure relates to a composition for an etching process,and more particularly, to a high-selectivity etching composition capableof selectively removing a nitride layer while minimizing an etch rate ofan oxide layer and to a method for fabricating a semiconductor using theetching composition.

In manufacturing semiconductors, an oxide layer and a nitride layer havebeen used as an insulating layer. The oxide layer may include a siliconoxide (SiO₂) layer, and the nitride layer may include a silicon nitride(SiN₂) layer. The silicon oxide layer and the silicon nitride (SiN₂)layer are used independently or alternatively stacked with each other asthe insulating layer. Furthermore, the oxide layer and the nitride layermay be used as a hard mask for forming a conductive pattern for metalinterconnections.

A wet etching process may be carried out for removing such a nitridelayer. Typically, as an etching composition, a mixture of a phosphoricacid and deionized water is used for removing the nitride layer. Thedeionized water may be added to prevent deterioration of an etching rateand variation of etching selectivity. However, even small variation in asupplied amount of the deionized water might cause defects in theetching process for removing the nitride layer. Furthermore, it is verydifficult to handle the phosphoric acid because the phosphoric acid hasstrong acid property and has corrosiveness or causticity.

In order to overcome such defect of the typical etching composition,etching composition including phosphoric acid (H₃PO₄) mixed with one ofhydrofluoric acid (HF) and nitric acid (HNO₃) was introduced. However,such etching composition deteriorates the etching selectivity of anitride layer and an oxide layer. Another etching composition includinga phosphoric acid and one of a silicate and a silicic acid wasintroduced. However, the silicate and the silicic acid cause generatingparticles that badly influence a substrate.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that is further described below in the DetailedDescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Embodiments of the present invention overcome the above disadvantagesand other disadvantages not described above. Also, embodiments of thepresent invention are not required to overcome the disadvantagesdescribed above, and embodiments of the present invention may notovercome any of the problems described above.

In accordance with an aspect of the present embodiment, an etchingcomposition may be provided for selectively removing a nitride layerwith minimizing an etching rate of an oxide layer.

In accordance with another aspect of the present embodiment, an etchingcomposition having high selectivity may be provided for preventinggeneration of particles during an etching process.

In accordance with still another aspect of the present embodiment, amethod may be provided for manufacturing a semiconductor using anetching composition having high selectivity for selectively removing anitride layer while minimizing an etching rate of an oxide layer.

In accordance with at least one embodiment, a composition may include afirst inorganic acid, at least one of silane inorganic acid saltsproduced by reaction between a second inorganic acid and a silanecompound, and a solvent. The second inorganic acid may be at least oneselected from the group consisting of a sulfuric acid, a fuming sulfuricacid, a nitric acid, a phosphoric acid, an anhydrous phosphoric acid,and a combination thereof. The silane compound may be a compoundrepresented by a first formula:

where each one of R1 to R4 is selected from the group consisting ofhydrogen, halogen, (C1-C10) alkyl, (C1-C10) alkoxy, and (C6-C30) aryl,and at least one of R1 to R4 is one of halogen and (C1-C10) alkyl.

In accordance with another embodiment, a composition may include a firstinorganic acid, at least one of silane inorganic acid salts produced byreaction between a polyphosphoric acid and a silane compound, and asolvent.

In accordance with another embodiment, a composition may include a firstinorganic acid, at least one of siloxane inorganic acid salts generatedthrough reaction between a second inorganic acid and a siloxanecompound, and a solvent. The second inorganic acid may be one selectedfrom the group consisting of a phosphoric acid, an anhydrous phosphoricacid, a pyrophosphoric acid, a polyphosphoric acid, and a combinationthereof.

In accordance with another embodiment, a composition may include a firstinorganic acid, at least one of siloxane inorganic acid salts generatedthrough reaction between a second inorganic acid and a siloxanecompound, and a solvent. The second inorganic acid may be one selectedfrom the group consisting of a sulfuric acid, a fuming sulfuric acid,and a combination thereof.

In accordance with another embodiment, a composition may include a firstinorganic acid, at least one of siloxane inorganic acid salts producedthrough reaction induced between a second inorganic acid including anitric acid and a siloxane compound, and a solvent.

In accordance with another embodiment, a composition may include a firstinorganic acid, at least one of silane inorganic acid salts generated byreaction induced between a second inorganic acid and a first silanecompound, a second silane compound, and a solvent. The second inorganicacid may be one selected from the group consisting of a sulfuric acid, afuming sulfuric acid, a nitric acid, a phosphoric acid, an anhydrousphosphoric acid, a pyrophosphoric acid, a polyphosphoric acid, and acombination thereof. The first silane compound and the second silanecompound may be one selected from the group consisting of compoundsrepresented by a tenth formula, compounds represented by an eleventhformula, and a combination thereof. The tenth formula is:

and

wherein the eleventh formula is:

where i) each one of R¹ to R¹⁰ is selected from the group consisting ofhydrogen, halogen, (C1-C10) alkyl, (C1-C10) alkoxy, and (C6-C30) aryl,ii) at least one of R¹ to R4 is one of halogen and (C1-C10) alkoxy, iii)at least one of R5 to R10 is one of halogen and (C1-C10) alkoxy, and iv)n is one of integer numbers from 1 to 10.

In accordance with another embodiment, a method may be provided forfabricating a semiconductor device. The method may include an etchingprocess carried out using the etching composition.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects of the present invention will becomeapparent and more readily appreciated from the following description ofembodiments, taken in conjunction with the accompanying drawings, ofwhich:

FIG. 1A and FIG. 1B illustrate a device isolation process for a flashmemory device;

FIG. 2A to FIG. 2C are cross-sectional views showing a device isolationprocess for a flash memory device in accordance with at least oneembodiment;

FIG. 3A to 3F are cross-sectional views showing a process of formingchannels for a flash memory device in accordance with at least oneembodiment;

FIGS. 4A and 4B are cross-sectional views illustrating a process offorming a diode for a phase-change memory device in accordance with atleast one embodiment; and

FIG. 5 is a graph showing nuclear magnetic resonance (NMR) data ofsilane inorganic acid slats produced according to the first embodimentA.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to like elementsthroughout. The embodiments are described below, in order to explain thepresent invention by referring to the figures.

The drawings are not necessarily to scale and in some instances,proportions may have been exaggerated in order to clearly illustratefeatures of the embodiments. When a first layer is referred to as being“on” a second layer or “on” a substrate, it not only refers to a casewhere the first layer is formed directly on the second layer or thesubstrate but also refers to a case where a third layer exists tobetween the first layer and the second layer or the substrate.

Throughout the specification, a term “(C₁-C₁₀) alkyl” denotes astraight-chain or branched non-cyclic saturated hydrocarbon having 1 to10 carbon atoms, and a term “(C₁-C₁₀) alkoxy” means a straight-chain orbranched non-cyclic hydrocarbon having one or more ether groups and 1 to10 carbon atoms.

In accordance with at least one embodiment, an etching composition mayinclude a first inorganic acid, at least one of silane inorganic acidsalts, and a solvent. The at least one of silane inorganic acid saltsmay be generated by reaction between a second inorganic acid and asilane compound.

The at least one of silane inorganic acid salts contained in the etchingcomposition may enable easy and effective control of an etch rate of anoxide layer and also enable easy control of an effective field oxideheight (EFH) in manufacturing a semiconductor device in accordance withat least one embodiment.

Hereinafter, such an etching composition in accordance with at least oneembodiment will be described with reference to the accompanyingdrawings. Prior to describing the etching composition in accordance withat least one embodiment, typical use of an etching composition inmanufacturing a semiconductor device will be described with reference toFIG. 1A to FIG. 1B.

FIG. 1A and FIG. 1B illustrate a device isolation process for a flashmemory device. Referring to FIG. 1A, tunnel oxide file 11, polysiliconlayer 12, buffer oxide layer 13, and pad nitride layer 14 aresequentially formed on substrate 10. At least one trench is formed byselectively etching polysilicon layer 12, buffer oxide layer 13, and padnitride layer 14. A gap filling process is carried out for filling theat least one trench by forming SOD oxide layer 15. Then, a chemicalmechanical polishing (CMP) process may be carried out using pad nitridelayer 14 as a polishing stopper layer.

Referring to FIG. 1B, pad nitride layer 14 is removed by performing awet etching process using a phosphoric acid solution. Buffer oxide layer13 is removed through a cleaning process. As a result, element isolationlayer 15A is formed. However, when the phosphoric acid solution is usedin the wet etching process, the etching selectivity of the nitride layerand the oxide layer is degraded. Due to such degradation, SOD oxidelayer 15 may be removed as well as pad nitride layer 14, and it isdifficult to control an effective field oxide height (EFH). Accordingly,due to the phosphoric acid solution, it is difficult i) to secure asufficient time for wet etching to remove pad nitride layer 14, ii) anadditional process may be required, and iii) the phosphoric acidsolution causes variation that badly influences device properties.

Therefore, there is a demand for a high selectivity etching compositionhaving high in order to selectively etch a nitride layer in respect toan oxide layer without generating particle.

In order to overcome defects of a typical etching composition andsatisfy the demand, a high selectivity etching composition forselectively removing a nitride layer while minimizing an etch rate of anoxide layer is provided in accordance with at least one embodiment. Suchan etching composition may include a first inorganic acid, at least oneof silane inorganic acid salts, and a solvent. The at least one ofsilane inorganic acid salts may be produced by reaction between a secondinorganic acid and a silane compound in accordance with at least oneembodiment.

Due to the at least one of silane inorganic acid salts contained in theetching composition, easy and effective control of an etch rate of anoxide layer may be enabled. Accordingly, an effective field oxide height(EFH) may be easily and effectively controlled in manufacturing asemiconductor device in accordance with at least one embodiment.

As described, the at least one of silane inorganic acid salts may beproduced as a result of repeated and continuous reaction between thesecond inorganic acid and the silane compound. Accordingly, the at leastone of silane inorganic acid salts may include various chemical formulasinstead of having single chemical formula.

The second inorganic acid may be one selected from the group consistingof a sulfuric acid, a fuming sulfuric acid, a nitric acid, a phosphoricacid, an anhydrous phosphoric acid, a pyrophosphoric acid, apolyphosphoric acid, and a combination thereof. Preferably, the secondinorganic acid may be one of a sulfuric acid, a nitric acid, and aphosphoric acid.

The silane compound may be one selected from the group consisting ofcompounds represented by Formulas A1 to A2 below and a combinationthereof.

In the Formula A1, each one of R¹ to R⁴ may be selected from the groupconsisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and(C₆-C₃₀) aryl. Furthermore, at least one of R¹ to R⁴ may be one ofhalogen and (C₁-C₁₀) alkyl.

The halogen may include fluoro, chloro, bromo, and iodo. Preferably, thehalogen may be one of fluoro and chloro.

In particular, the silane compound represented by the Formula A1 mayinclude a halo silane compound and an alkoxy silane compound.

The halo silane compound may be selected from the group consisting oftrimethylchlorosilane, triethylchlorosilane, tripropylchlorosilane,trimethylfluorosilane, triethylfluorosilane, tripropylfluorosilane,dimethyldichlorosilane, diethyldichlorosilane, dipropyldichlorosilane,dimethyldifluorosilane, diethyldifluorosilane, dipropyldifluorosilane,ethyltrichlorosilane, propyltrichlorosilane, methyltrifluorosilane,ethyltrifluorosilane, propyltrifluorosilane, and the combinationthereof.

The alkoxy silane compound may be selected from the group consisting oftetramethoxysilane, tetrapropoxysilane, methyltrimethoxysilane (MTMOS),methyltriethoxysilane (MTEOS), methyltripropoxysilane,ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane,propyltrimethoxysilane (PrTMOS), propyltriethoxysilane (PrTEOS),propyltripropoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane,dimethyldipropoxysilane, diethyldimethoxysilane, diethyldiethoxysilane,diethyldipropoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane,dipropyldipropoxysilane, trimethylmethoxysilane, trimethylethoxysilane,trimethylpropoxysilane, triethylmethoxysilane, triethylethoxysilane,triethylpropoxysilane, tripropylmethoxysilane, tripropylethoxysilane,tripropylpropoxysilane, 3-chloropropyltrimethoxysilane,3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,[3-(2-aminoethyl)aminopropyl]trimethoxysilane,3-mercaptopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane,3-acryloxypropyltrimethoxysilane, and the combination thereof.

In the Formula A2, each one of R⁵ to R¹⁰ may be selected from the groupconsisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and(C₆-C₃₀) aryl. Furthermore, at least one of R⁵ to R¹⁰ may be one ofhalogen and (C₁-C₁₀) alkoxy, and n is one of integer numbers from 1 to10.

The halogen may include fluoro, chloro, bromo, and iodo. Preferably, thehalogen may be one of fluoro and chloro.

In particular, the compounds represented by the Formula A2 may includechlorodimethylsiloxy-chlorodimethyl silane,chlorodiethylsiloxy-chlorodimethylsilane,dichloromethylsiloxy-chlorodimethyl silane,dichloroethylsiloxy-chlorodimethylsilane, trichlorosiloxy-chlorodimethylsilane, fluorodimethyl siloxy-chlorodimethyl silane, difluoromethylsiloxy-chlorodimethyl silane, trifluorosiloxy-chlorodimethyl silane,methoxydimethylsiloxy-chlorodimethyl silane,dimethoxydimethylsiloxy-cholrodimethylsilane,trimethoxysiloxy-chlorodimethylsilane, ethoxy dim ethylsiloxy-chlorodimethyl silane, diethoxymethylsiloxy-chlorodimethylsilane,triethoxysiloxy-chlorodimethyl silane,chlorodimethylsiloxy-dichloromethylsilane,trichlorosiloxy-dichloromethyl silane,chlorodimethylsiloxy-trichlorosilane,dichloromethylsiloxy-trichlorosilane, andtrichlorosiloxy-trichlorosilane.

The silane inorganic acid salts may be produced by i) adding the silanecompound with the second inorganic acid and ii) inducing reaction withina temperature range from about 20° C. to about 300° C., preferably, atemperature range from about 50° C. to about 200° C. Such a process maybe carried out while removing air and moisture. When a reactiontemperature is lower than about 20° C., the silane compound may becrystallized or vaporized due to a comparatively low reaction rate. Whena reaction temperature is higher than about 300° C., the secondinorganic acid may be vaporized.

For example, about 100 part of weight of the second inorganic acid maybe reacted with about 0.001 to about 50 part of weight of the silanecompound. Preferably, about 0.01 to about 30 part of weight of thesilane compound may be reacted with about 100 part of weight of thesecond inorganic acid. When the content of the silane compound issmaller than about 0.01 part of weight, it is difficult to obtaindesired selectivity. When the content of the silane compound is greaterthan about 50 part of weight, the silane compound might be crystallizedand form irregular structures.

During the reaction, volatile by-product may be generated. Such volatileby-product may be removed through distillation with decompression. Suchreaction result may be distillated and the silane inorganic acid saltsare isolated therefrom. The isolated silane inorganic acid salts areadded into the etching composition. However, the present embodiment isnot limited thereto. For example, the reaction result may be added intothe etching composition without the distillation.

Such reaction may be carried out with or without an aprotic solvent. Incase of using the non-protic solvent, it is preferable to use a solventor a solvent mixture having a boiling point up to 120° C. as 10013 mbar.Such a solvent may include: i) dioxane, tetrahydrofuran, diethyl ether,diisopropyl ether, diethylene glycol methyl ether; ii) chlorinatedhydrocarbons, such as dichloromethane, trichloromethane,tetrachloromethane, 1,2-dichloroethane, and trichlorethylene; iii)hydrocarbons, such as pentane, n-hexane, hexane isomer mixture, heptane,octane, benzene, petroleum ether, benzene, toluene, and xylene; iv)ketones such as acetone, methyl ethyl ketone, diisopropyl ketone, andmethyl isobutyl ketone (MIBK); v) esters, such as ethyl acetate, butylacetate, propyl propionate, ethyl butyrate ethyl isobutyrate, carbondisulphide and nitrobenzene; and a combination thereof.

As described, the silane inorganic acid salts are produced by inducingreaction between the second inorganic acid and the silane compound.Accordingly, the silane inorganic acid salts have various chemicalformulas in accordance with at least one embodiment. That is, the silaneinorganic acid salts may be produced by repeated and continuousreactions between the second inorganic acid and the silane compound.Such silane inorganic acid slats may have various straight-chain orbranched formula structures reacted according to the number of halogenatoms and positions of the halogen atoms.

Such silane inorganic acid salts may be exemplary expressed by followingFormulas. However, the present embodiments are not limited thereto.

In the Formulas A3-1 to A3-7, A4-1 to A4-7, and A5-1 to A5-7, each oneof R¹⁻¹ to R¹⁻⁸ may be selected from the group consisting of hydrogen,halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and (C₆-C₃₀) aryl. The halogenmay include fluoro, chloro, bromo, and iodo. Preferably, the halogen maybe one of fluoro and chloro.

The content of the silane inorganic acid salts is about 0.01 to about 15wt %, more preferably about 0.05 to about 15 wt %, even more preferablyabout 1 to about 15 wt %, and more preferably about 3 to about 7 wt %,based on the total weight of the etching composition.

When the content of the silane inorganic acid salts is less than about0.01 wt %, a high etching selectivity for a nitride layer may not beobtained. When the content of the silane inorganic acid salts is morethan about 15 wt %, an increase in the content does not lead to afurther increase in the etching selectivity and may cause problems suchas generation of particles.

For example, when the content of the silane inorganic acid salts is morethan about 0.7 wt %, a selectivity between a nitride etch rate and anoxide etch rate of the etching composition is higher than about 200:1(e.g., nitride etch rate Å/min: oxide etch rate Å/min). For example, theselectivity of the etching composition may be about 200:1, about 200:5,and about 200:10.

For example, when the content of the silane inorganic acid salts ishigher than about 1.4 wt %, the selectivity between the nitride etchrate and the oxide etch rate of the silane inorganic acid salts may beabout 200:infinity (nitride etch rate: oxide etch rate). As described,the etching composition in accordance with at least one embodiment has ahigh selectivity for a nitride layer with respect to an oxide layer.Accordingly, the etching composition enables easy control of the etchrate of the oxide layer and easy control of the EFH.

In accordance with at least one embodiment, the silane inorganic acidslats may be produced by reacting polyphosphoric acid with silanecompounds. Such silane inorganic acid slats may be represented byFormula B1 below.

In the Formula B1, R¹ may be selected from the group consisting ofhydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and (C₆-C₃₀) aryl.The halogen may include fluoro, chloro, bromo, and iodo. Preferably, thehalogen may be one of fluoro and chloro. n₁ is one of integer numbersfrom 1 to 4, and m₁ is one of integer numbers from 1 to 10. Each one ofR² to R⁴ may be hydrogen. Selectively, at least one of hydrogensselected from the group consisting of R² to R⁴ may be substituted by asubstituent represented by Formula B2 below.

In the Formula B2, one of R⁵ may be a coupler to Formula B1 and theothers may be selected from the group consisting of hydrogen, halogen,(C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and (C₆-C₃₀) aryl. For example, whenthere are four R⁵, one of R⁵ is a coupler to Formula B1, each one of theremaining three R⁵ may be selected from the group consisting ofhydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and (C₆-C₃₀) aryl.For another example, when there is one R⁵, it is a coupler to FormulaB1. n₂ is one of integer numbers from 0 to 3, and m₂ is one of integernumbers from 1 to 10.

In the Formula B2, each one of R² to R⁴ may be hydrogen or may besubstituted by a substituent represented by Formula B2. That is, one ofR² to R⁴ may be substituted by a substituent represented by Formula B2.In addition, one of R² to R⁴ of a substituent represented by a secondFormula B2 may be also substituted by a substituent represented by athird Formula B2

It is because the silane inorganic acid salts are produced by reactionbetween the polyphosphoric acid and the silane compound. For example, acomposition represented by the Formula B1 is produced by reactionbetween the polyphosphoric acid and the silane compound. In the producedcomposition represented by the Formula B1, hydroxyl group may be reactedagain with the silane compound. Herein, the hydroxyl group is positionedone of R² to R⁴ at a part induced from the polyphosphoric acid, and thesilane compound is a reactant starting this repeated reaction.Continuously, the reacted silane compound is reacted again with thepolyphosphoric acid. Such reaction may be repeated and continued.

As a result of repeated and continuous reaction, the followingcompositions of the silane inorganic acid salts may be produced

In the Formula B1, n₁ is 1, m₁ is 1, R² to R⁴ are all hydrogen. In thiscase, a silane inorganic acid salt represented by Formula B3-1 below maybe produced. The definition of R¹⁻¹ to R¹⁻³ is identical to thedefinition of the R¹.

A composition represented by Formula B3-2 below is about identical tothe composition represented by Formula B3-1 except m₁ is 2.

Formula B3-3 below exemplary expresses a compound when the Formula B1has following conditions: i) n₁ is 2, ii) m₁ is 1, and iii) each one ofR² to R⁴ is hydrogen. The definitions of R¹⁻¹ to R¹⁻² are identical tothe definition of the R¹.

Formula B3-4 below exemplary expresses a compound when Formula B1 hasfollowings: i) n₁ is 1, ii) m₁ is 1, iii) all of R² to R³ is hydrogen,and iv) R⁴ is substituted by a substituent expressed by the Formula B2.In the Formula B2 of the substituent, n₂ is 0, and at least one of R⁵ isa coupler to Formula B1. Herein, definitions of R¹⁻¹ to R¹⁻⁶ areidentical to the definition of R¹.

Such a compound represented by the Formula B3-4 below is produced as aresult of repeated reaction between i) a part induced from thepolyphosphoric acid having a substituent of R⁴ of the compoundrepresented by Formula B1 and ii) the silane compound. Herein, thesilane compound is a reactant starting the repeated reaction.

Formula B3-5 below exemplary represents a compound when the Formula B1has followings: i) n₁ is 1, ii) m₁ is 1, iii) R³ to R⁴ are hydrogen, andiv) R² is substituted by Formula B2. Herein, the Formula B2 hasfollowings: i) n₂ is 1, ii) m₂ is 1, iii) at least one of R⁵ is acoupler to Formula B1, and iv) all of R² to R⁴ is hydrogen. Herein,definitions of R¹⁻¹ to R¹⁻⁵ are identical to the definition of R¹.

Such a compound represented by the Formula B3-5 below is produced as aresult of repeated and continuous reactions. For example, i) hydroxylgroup, which is positioned at the location of R⁴ of a part induced fromthe polyphosphoric acid in the compound represented by Formula B1, isreacted again with the silane compound. Herein, the silane compound is areactant starting this repeated reaction. Then, ii) the silane compoundreacted with the compound represented by the Formula B1 is continuouslyreacted with the polyphosphoric acid. Herein, the polyphosphoric acid isa reactant starting this continues reaction.

Formula B3-6 and Formula B3-7 below exemplary represents compounds aboutidentical to the compound represented by the Formula B3-5 except alocation of a substituent expressed by the Formula B2. In case of theFormula B3-6, the substituent expressed by the Formula B2 is positionedat a location of R³ of the Formula B1. In case of the Formula B3-7, thesubstituent expressed by the Formula B2 is positioned at a location ofR⁴ of the Formula B1.

Formula B3-8 below exemplary represents a compound when the Formula B1has following conditions: i) n₁ is 1, ii) m₁ is 1, iii) R² to R³ arehydrogen, iv) R⁴ of the Formula B1 is substituted by a first substituentexpressed by the Formula B2, and v) R⁴ of the substituent expressed bythe Formula B2 is substituted by a second substituent expressed by theFormula B2. Herein, the Formula B2 has following conditions: i) n₂ is 1,ii) m₂ is 1, iii) at least one of R⁵ is a coupler to the Formula B1, andiv) at least one of R² and R³ is hydrogen. Herein, definitions of R¹⁻¹to R¹⁻⁷ are identical to the definition of R¹.

Such a compound represented by the Formula B3-8 below is produced as aresult of repeated and continuous reactions. For example, i) hydroxylgroup is reacted again with the silane compound. Herein, the reactedhydroxyl group is positioned at a part induced from the polyphosphoricacid at a right end of the compound represented by the Formula B3-7, andthe silane compound is a reactant starting this repeated reaction. Then,ii) the silane compound reacted with the compound represented by theFormula B3-7 is continuously reacted with the polyphosphoric acid.Herein, the polyphosphoric acid is a reactant starting this continuousreaction.

As described, various compositions expressed by the Formula B3-1 to B3-8may be produced in accordance with at least one embodiment. However, theembodiments are not limited thereto.

As described, the silane compounds may be reacted with thepolyphosphoric acid and produce silane inorganic acid salts expressed bythe Formula B1 as a result of the reaction. Such silane compounds may bea compound represented by the Formula A1. Since the compounds expressedby the Formula A1 are already described, the detailed descriptionsthereof are omitted herein.

The polyphosphoric acid may be a pyrophosphoric acid containing twophosphoric acid atoms or a polyphosphate containing three or morephosphoric acid atoms.

A method of producing the silane inorganic acid salts by reacting thepoly phosphoric acid and the silane compound may be about identical to amethod of producing silane inorganic acid salts by reacting the secondinorganic acid with the silane compounds, except using thepolyphosphoric acid instead of using the second inorganic acid.

In accordance with at least one embodiment, the silane inorganic acidsalts may be siloxane inorganic acid salts expressed by Formula C1below. Such siloxane inorganic acid salts may be produced by reacting asecond inorganic acid and a siloxane compound. Herein, the secondinorganic acid may be selected from the group consisting of phosphoricacid, anhydrous phosphoric acid, pyrophosphoric acid, polyphosphoricacid, and a combination thereof.

In the Formula C1, each one of R¹ to R² may be selected from the groupconsisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and(C₆-C₃₀) aryl. The halogen may include fluoro, chloro, bromo, and iodo.Preferably, the halogen may be one of fluoro and chloro.

In the Formula C1, n₁ is one of integer numbers from 0 to 3, n₂ is oneof integer numbers from 0 to 2, and m₁ is one of integer numbers 0 and1, wherein a sum of n₁, n₂, and m₁ is equal or greater than 1 (e.g.,n₁+n₂+m₁≥1). For example, the Formula C1 may include at least one ofatom groups induced from the second inorganic acid such as thephosphoric acid.

In the Formula C1, l₁ is one of integer numbers from 1 to 10 and eachone of O₁ to O₃ is one of integer numbers from 0 to 10.

In the Formula C1, each one of R³ to R¹¹ is hydrogen. Selectively, atleast one of hydrogen selected from the group consisting of R³ to R¹¹may be substituted by a substituent expressed by Formula C2 below.

In the Formula C2, one of R¹² and R¹³ may be a coupler to the Formula C1and the others may be independently selected from the group consistingof hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and (C₆-C₃₀)aryl. For example, when there are two R¹² and one R¹³, one of them is acoupler to the Formula C1, each one of the remaining two may be selectedfrom the group consisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀)alkoxy, and (C₆-C₃₀) aryl. For another example, when there is one R¹²and none of R¹³, R¹² is a coupler to the Formula C1.

n₃ is one of integer numbers from 0 to 3, n₄ is one of integer numbersfrom 0 to 2, and m₁ is one of integer numbers from 0 to 1. l₁ is one ofinteger numbers from 1 to 10, and each one of O₁ to O₃ is one of integernumbers from 0 to 10.

In the Formula C2, R³ to R¹¹ may be hydrogen or may be substituted by asubstituent expressed by the Formula C2, referred to as second FormulaC2. That is, at least one of R³ to R¹¹ of the Formula C2 may besubstituted by a substituent expressed by the second Formula C2, and atleast one of R³ to R¹¹ of the second Formula C2 may be substituted againby a substituent expressed by the Formula C2, referred to as thirdFormula C2.

It is because the siloxane inorganic acid salts are produced throughrepeated and continuous reaction the second inorganic acid and thesiloxane compound. For example, a compound represented by the Formula C1is produced through reaction between the second inorganic acid and thesiloxane compound. In the produced compound represented by the FormulaC1, hydroxyl group is reacted with the siloxane compound again. Herein,the siloxane compound is a reactant starting this repeated reaction, andthe hydroxyl group reacted with the siloxane is positioned at locationsof the R³ to R¹¹ of a part induced from the second inorganic acid.Continuously, the siloxane compound, reacted with the produced compoundexpressed by the Formula C1, is reacted with the second inorganic acidagain. Herein, the second inorganic acid is a reactant starting thiscontinuous reaction. Such reactions are repeated and continued.

Following formulas exemplarily show siloxane inorganic acid saltsproduced as results of such repeated and continuous reactions.

Formula C1-1 below exemplary expresses a compound when the Formula C1has following conditions: i) n₁ is 1, ii) n₂ is 0, iii) m₁ is 0, iv) l₁is 1, v) O₁ to O₃ are 0, vi) all of R³ to R¹¹ is hydrogen. Herein,definitions of R¹⁻¹ to R¹⁻² are identical to the definition of R¹, anddefinitions of R²⁻¹ to R²⁻² are identical to the definition of R².

Formula C1-2 below expresses a compound about identical to the compoundrepresented by the Formula C1-1 except when n₂ is 1.

Formula C1-3 below expresses a compound that is about identical to thecompound represented by the Formula C1-1 except when O₂ and O₃ are 1.

Formula C1-4 below expresses a compound that is about identical to thecompound represented by the Formula C1-2 except when l₁ is 2.

Formula C1-5 below exemplary expresses a compound when the Formula C1has following conditions: i) n₁ is 2, ii) n₂ is 2, iii) m₁ is 0, iv) l₁is 1, v) at least one of O₁ to O₃ is 0, vi) all of R³ to R¹¹ ishydrogen.

Formula C1-6 below exemplary expresses a compound when the Formula C1has following conditions: i) n₁ is 1, ii) n₂ is 1, iii) m₁ is 0, iv) l₁is 1, v) at least one of O₁ to O₃ is 0, vi) R⁶, R⁹, and R¹¹ arehydrogen, and vii) R⁸ is substituted by a substituent expressed by theFormula C2. Herein, in the Formula C2 of the substituent, i) n₃ and n₄are 0, ii) m₁ is 0, iii) l₁ is 1, and iv) at least one of R¹² is acoupler to the Formula C1.

Herein, definitions of R¹⁻¹ to R¹⁻⁷ are identical to the definition ofR¹, and definition of R²⁻¹ is identical to the definition of R². Such acompound represented by the Formula C1-6 below is produced as a resultof repeated reaction between i) hydroxyl group and ii) the siloxanecompound. The reacted hydroxyl group is positioned at a location of R⁸of a part induced from the second inorganic acid in the compoundexpressed by the Formula C1, and the siloxane compound is a reactantstarting this repeated reaction.

Formula C1-7 below exemplary expresses a compound when the Formula C1has following conditions: i) n₁ is 1, ii) n₂ is 1, iii) m₁ is 0, iv) l₁is 1, v) at least one of O₁ to O₃ is 0, vi) R⁶, R⁹, and R¹¹ arehydrogen, and vii) R⁸ is substituted by a substituent expressed by theFormula C2. Herein, in the Formula C2 of the substituent, i) n₃ and n₄are 1, ii) m₁ is 0, iii) O₂ and O₃ are 0, iv) at least one of R¹² is acoupler to the Formula C1, and v) R⁶, R⁸, R⁹, and R¹¹ are hydrogen.Herein, definitions of R¹⁻¹ to R¹⁻³, R²⁻¹, R²⁻², R³⁻¹, and R³⁻² areidentical to the definitions of R¹, R², and R³, respectively.

Such a compound represented by the Formula C1-7 below is produced as aresult of repeated and continuous reactions. For example, hydroxyl groupis reacted again with the siloxane compound. Herein, the reactedhydroxyl group is hydroxyl group positioned at the R⁸ of a part inducedfrom the second inorganic acid in the compound expressed by the FormulaC1. Then, the reacted siloxane compound is continuously reacted with thesecond inorganic acid. Herein, the second inorganic acid is a reactantstarting this continuous reaction.

Formula C1-8 below expresses a compound that is about identical to thecompound represented by the Formula C1-7 except that a substituentexpressed by the Formula C2 is positioned at a location of R¹⁻³ of theFormula C1-7 and coupled to the Formula C1.

Formula C1-9 below exemplary expresses a compound when the Formula C1has following conditions: i) n₁ is 1, ii) n₂ is 1, iii) m₁ is 0, iv) l₁is 1, v) at least one of O₁ to O₃ is 0, vi) R³, R⁶, R⁹, and R¹¹ arehydrogen, vii) R⁸ of the Formula C1 is substituted by a firstsubstituent expressed by the Formula C2 referred to as first Formula C2,and viii) R⁸ of the first substituent (e.g., the first Formula C2) issubstituted by a second substituent expressed by the Formula C2 referredto as second Formula C2. Herein, in the first Formula C2 of the firstsubstituent, i) n₃ and n₄ are 1, ii) m₁ is 0, iii) l₁ is 1, iv) O₂ andO₃ are 0, v) at least one of R¹² is a coupler to the Formula C1, v) R⁶,R⁹, and R¹¹ are hydrogen, and vi) R⁸ is the second substituent expressedby the second Formula C2. In the second Formula C2 of the secondsubstituent, i) n₃ and n₄ are 1, ii) m₁ is 0, iii) l₁ is 1, iv) O₂ andO₃ are 0, v) at least one of R¹² is a coupler to the first Formula C2,and v) R⁶, R⁸, R⁹, and R¹¹ are hydrogen. Herein, definitions of R¹⁻¹ toR¹⁻⁴, and R³⁻¹ to R³⁻³ are identical to the definitions of R¹, R², andR³, respectively.

Such a compound represented by the Formula C1-9 below is produced as aresult of repeated and continuous reactions. For example, a part inducedfrom the second inorganic acid at a right end of the compound expressedby the Formula C1-7 is reacted again with the siloxane compound. Then,the reacted siloxane compound is continuously reacted with the secondinorganic acid. Herein, the second inorganic acid is a reactant startingthis continuous reaction.

Formula C1-10 below expresses a compound that is about identical to thecompound represented by the Formula C1-9 except that a substituentexpressed by the Formula C2 is positioned at a location of R¹⁻⁴ of theFormula C1-9 and coupled to the Formula C1.

Compounds in accordance with embodiments are not limited to thecompounds expressed by the Formulas C1-1 to C1-10.

For example, in accordance with at least one embodiment, the silanecompound may be siloxane inorganic acid salts which is represented byFormula C3 below and produced by reacting a second inorganic acid and asiloxane compound. Herein, the second inorganic acid may be selectedfrom the group consisting of sulfuric acid, fuming sulfuric acid, and acombination thereof.

In the Formula C3, each one of R²¹ and R²² may be independently selectedfrom the group consisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀)alkoxy, and (C₆-C₃₀) aryl. The halogen may include fluoro, chloro,bromo, and iodo. Preferably, the halogen may be one of fluoro andchloro.

In the Formula C3, n₁ is one of integer numbers from 0 to 3, n₂ is oneof integer numbers from 0 to 2, and m₁ is one of integer numbers 0 and1, wherein a sum of n₁, n₂, and m₁ is equal or greater than 1 (e.g.,n₁+n₂+m₁≥1). For example, the Formula C3 may include at least one ofatom groups induced from the second inorganic acid such as the sulfuricacid.

In the Formula C3, l₁ is one of integer numbers from 1 to 10.

In the Formula C3, each one of R²³ to R²⁵ is hydrogen. Selectively, atleast one of hydrogen selected from the group consisting of R²³ to R²⁵may be substituted by a substituent expressed by Formula C4 below.

In the Formula C4, one of R²⁶ and R²⁷ may be a coupler to the Formula C3and the others may be independently selected from the group consistingof hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and (C₆-C₃₀)aryl. For example, when there are two R²⁶ and one R²⁷, one of them is acoupler to the Formula C3, each one of the remaining two may be selectedfrom the group consisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀)alkoxy, and (C₆-C₃₀) aryl. For another example, when there is one R²⁶and none of R²⁷, R²⁶ is a coupler to the Formula C3.

In the Formula C4, n₃ is one of integer numbers from 0 to 3, n₄ is oneof integer numbers from 0 to 2, m₁ is one of integer numbers from 0 to1, and l₁ is one of integer numbers from 1 to 10.

In the Formula C4, R²³ to R²⁵ may be independent and hydrogen. R²³ toR²⁵ may be substituted by a substituent expressed by the Formula C4,referred to as second Formula C4. That is, at least one of R²³ to R²⁵ ofthe Formula C4 may be substituted by a substituent expressed by thesecond Formula C2, and at least one of R²³ to R²⁵ of the second FormulaC4 may be substituted again by a substituent expressed by the FormulaC4, referred to as third Formula C4.

Following Formulas C3-1 to C3-9 exemplarily show siloxane inorganic acidsalts produced as results of the above repeated and continuousreactions, similarly to Formulas C1-1 to C1-10. In the Formulas C3-1 toC3-9, definitions of R¹¹⁻¹ to R¹¹⁻⁷, R¹²⁻¹ to R¹²⁻³, and R¹³⁻¹ to R¹³⁻³are identical to the definitions of R¹¹, R¹², and R¹³.

The compounds in accordance with at least one embodiment are not limitedto the compounds expressed by the Formulas C3-1 to C3-9.

In accordance with at least one embodiment, the silane inorganic acidsalts may be silane inorganic acid salts which is produced by reacting asecond inorganic acid such as nitric acid and a siloxane compound. Suchsilane inorganic acid salts may be expressed by Formula C5 below.

In the Formula C5, one of R³¹ and R³² may be independently selected fromthe group consisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀)alkoxy, and (C₆-C₃₀) aryl. The halogen may include fluoro, chloro,bromo, and iodo. Preferably, the halogen may be one of fluoro andchloro.

In the Formula C5, n₁ is one of integer numbers from 0 to 3, n₂ is oneof integer numbers from 0 to 2, and m₁ is one of integer numbers 0 and1, wherein a sum of n₁, n₂, and m₁ is equal or greater than 1 (e.g.,n₁+n₂+m₁≥1). For example, the Formula C5 may include at least one ofatom groups induced from the second inorganic acid such as the nitricacid.

In the Formula C5, l₁ is one of integer numbers from 1 to 10.

In the Formula C5, each one of R³³ to R³⁵ is hydrogen. Selectively, atleast one of hydrogen selected from the group consisting of R³³ to R³⁵may be substituted by a substituent expressed by Formula C6 below.

In the Formula C6, one of R³⁶ and R³⁷ may be a coupler to the Formula C5and the others may be independently selected from the group consistingof hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and (C₆-C₃₀)aryl. For example, when there are two R³⁶ and one R³⁷, one of them is acoupler to the Formula C5, each one of the remaining two may be selectedfrom the group consisting of hydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀)alkoxy, and (C₆-C₃₀) aryl. For another example, when there is one R³⁶and none of R³⁷, R³⁶ is a coupler to the Formula C5.

In the Formula C6, n₃ is one of integer numbers from 0 to 3, n₄ is oneof integer numbers from 0 to 2, m₁ is one of integer numbers from 0 to1, and l₁ is one of integer numbers from 1 to 10.

In the Formula C6, R³³ to R³⁵ may be independent and hydrogen. R³³ toR³⁵ may be substituted by a substituent expressed by the Formula C6,referred to as second Formula C6. That is, at least one of R³³ to R³⁵ ofthe Formula C6 may be substituted by a substituent expressed by thesecond Formula C6, and at least one of R³³ to R³⁵ of the second FormulaC6 may be substituted again by a substituent expressed by the FormulaC6, referred to as third Formula C6.

Following Formulas C5-1 to C5-9 exemplarily show siloxane inorganic acidsalts produced as results of the above repeated and continuousreactions, similarly to the Formulas C1-1 to C1-10. In the Formulas C5-1to C5-9, definitions of R²¹⁻¹ to R²¹⁻⁷, R²²⁻¹ to R²²⁻³, and R²³⁻¹ toR²³⁻³ are identical to the definitions of R²¹, R²², and R²³.

As described, the embodiments are not limited to the compositionsexemplary expressed by the Formulas C5-1 to C5-9.

As described, in accordance with at least one embodiment, the siloxaneinorganic acid salts expressed by the Formula C1 may be produced throughreaction between the second inorganic acid with the siloxane compound.Such siloxane compounds may be a compound expressed by the Formula A2.Since the compound expressed by the Formula A2 is already describedabove, the detailed descriptions thereof are omitted herein.

A method of producing the siloxane inorganic acid salts by reacting thesecond inorganic acid with the siloxane compound may be about identicalto a method of producing silane inorganic acid salts by reacting thesecond inorganic acid with the silane compound, except using thesiloxane compound instead of the silane compound.

In accordance with another embodiment, a composition for etching mayinclude a first inorganic acid, at least one of silane inorganic acidsalts, and a solvent. The at least one of silane inorganic acid saltsmay be formed by reacting the second inorganic acid with a second silanecompound.

As described, the etching composition may additionally include thesecond silane compound with the silane inorganic acid salts. Suchadditional second silane compound may be reacted with the firstinorganic acid and produce additional silane inorganic acid salts duringan etching process performed using the etching composition. Accordingly,the additional second silane compound may further improve selectivityfor selectively removing a nitride layer while minimizing an etch rateof an oxide layer and prevention of generation of particles that badlyinfluencing device properties. In addition, the additional second silanecompound may additionally supply silane inorganic acid salts that areconsumed during an etching process.

As the second silane compound, the above described silane compound maybe used. Preferably, identical silane compounds, which are used forproducing silane inorganic acid salts, may be used as the second silanecompound. In this case, components of the second silane compound will besimilar to components of the silane inorganic acid salts. Accordingly,it might further improve the affection of adding the second silanecompound. Furthermore, it allows adding a reacting solution producingthe silane inorganic acid salts to the etching composition without arefining process. That is, unreacted second silane compound can beeffectively added into the etching composition.

The content of the second silane compound may be about 0.001 to about 15wt %, preferably about 0.005 to about 10 wt %, more preferably about0.01 to about 5 wt % based on the total weight of the etchingcomposition. When the second silane compound is added less than about0.001 wt %, it causes difficulties to control selectivity due tocomparatively small content of the second silane compound. When thesecond silane compound is added more than about 15 wt %, it causescrystallization or generation of by-product.

The first inorganic acid is added as an etching agent for etching anitride layer. Accordingly, the first inorganic acid may include anyinorganic acid capable of etching the nitride layer. For example, thefirst inorganic acid may be selected from the group consisting ofsulfuric acid, nitric acid, phosphoric acid, silicic acid, hydrofluoricacid, boric acid, hydrochloric acid, chloric acid, and a combinationthereof.

Preferably, phosphoric acid may be used as the first inorganic acid inorder to obtain an etching selectivity of the nitride layer in responseto the oxide layer. The phosphoric acid may accelerate etching byproviding hydrogen ions to the etching composition. In case of using thephosphoric acid as the first inorganic acid, the etching composition mayfurther include sulfuric acid as additive. The sulfuric acid mayincrease a boiling point of the etching composition containing thephosphoric acid as a first inorganic acid, thereby improving etching anitride layer.

The content of the first inorganic acid may be about 70 to 99 wt %,preferably about 70 to 90 wt %, and more preferably about 57 to about 85wt %. When the content of the first inorganic acid is less than about 70wt %, it might cause difficulties to effectively remove a nitride layerand generation of particles. When the content of the first inorganicacid is more than about 99 wt %, it may be difficult to obtain highselectively for a nitride layer.

As described, the etching composition may include solvent. Inparticular, the solvent may include water and deionized water.

The etching composition may further include an ammonium based compound.The content of the ammonium based compound may be about 0.01 to about 20wt %. The ammonium based compound included in the etching compositionmay prevent decrease of an etching rate and variation of selectivityalthough the etching composition is used in comparatively long time. Inaddition, the ammonium based compound may constantly sustain the etchingrate.

When the content of the ammonium based compound is less than about 0.01wt %, the advantageous effect of sustaining the selectivity may bedeteriorated. When the content of the ammonium based compound is morethan about 20 wt %, an etching rate between a nitride layer and asilicon oxide layer is changed. Accordingly, the selectivity may bechanged.

The ammonium based compound may be selected from the group consisting ofammonium hydroxide, ammonium chloride, ammonium acetate, ammoniumphosphate, ammonium peroxydisulfate, ammonium sulfate, ammoniumhydrofluoric acid salt, and a combination thereof. However, the ammoniumbased compound is not limited thereto. For example, the ammonium basedcompound may include compounds containing ammonium ion. For example, theammonium based compound may include NH₄ and HCl.

The etching composition may further include fluoride based compound. Thecontent of the fluoride based compound may be about 0.01 to about 1 wt%. When the content of the fluoride based compound is less than about0.01 wt %, it may decrease an etching rate of a nitride layer.Accordingly, it is difficult to remove a nitride layer. When the contentof the fluoride based compound is more than about 1 wt %, the etchingrate of the nitride layer may be significantly improved. However, anoxide layer may be etched unexpectedly.

The fluoride based compound may be selected from the group consisting ofhydrogen fluoride, ammonium fluoride, ammonium hydrogen fluoride, and acombination thereof. Preferably, the ammonium hydrogen fluoride may beused because it might improve sustaining selectivity although theetching composition is used in a comparatively long time.

In addition, the etching composition of the present embodiment mayfurther comprise any additive that is generally used in the art, inorder to improve the etching performance thereof. Examples of anadditive that may be used in the present embodiment include surfactants,sequestering agents, anti-corrosive agents and the like.

The etching composition of the present embodiment, comprising the silaneinorganic acid salts, shows a significantly high etching selectivity fora nitride layer with respect to an oxide layer, and thus may be used ina process for etching a nitride layer.

Thus, in the nitride film etching process employing the etchingcomposition of the present embodiment, the EFH may be easily controlledby minimizing the etch rate of an oxide film. In addition, in theprocess of selectively etching and removing of a nitride film using theetching composition, the deterioration in electrical properties causedby damage to an oxide film or etching of the oxide film may beprevented, and particles are not generated, which results in improvementof device properties.

In accordance with another aspect of embodiments, a method forfabricating a semiconductor device may be provided to include an etchingprocess carried out using the etching composition of the presentembodiment.

In one exemplary embodiment, this etching process may include etching anitride layer. Particularly, the etching process may include selectivelyetching a nitride film with respect to an oxide film.

The nitride layer may include SiN films, SiON films and the like.

In addition, an oxide film may be at least one film selected from thegroup consisting of silicon oxide films, for example, SOD(spin-on-dielectric) films, HDP (high-density plasma) films, thermaloxide films, BPSG (borophosphate silicate glass) films, PSG(phosphosilicate glass) films, BSG (borosilicate glass) films, PSZ(polysilazane) films, FSG (fluorinated silicate glass) films, LPTEOS(low-pressure tetraethylorthosilicate) films, PETEOS (plasma-enhancedtetraethylorthosilicate) films, HTO (high-temperature oxide) films, MTO(medium-temperature oxide) films, USG (undopped silicate glass) films,SOG (spin-on-glass) films, APL (advanced planarization layer) films, ALD(atomic layer deposition) films, plasma-enhanced oxide films, O3-TEOS(O3-tetraethylorthosilicate) films, and combinations thereof.

An etching process employing the etching composition of the presentembodiment may be performed by a wet-etching method known in the art,for example, a dipping method or a spray method.

The etching process may be carried out at a temperature range betweenabout 50° C. and about 300° C. and preferably about 100° C. and about200° C. The temperature of the etching process may be suitably changedin view of other processes and other factors.

In the method for fabricating a semiconductor device, including theetching process that is carried out using the etching composition of thepresent embodiment, a nitride film may be selectively etched from astructure in which a nitride film and an oxide film are stackedalternately or present together. In addition, particle generation, whichwas problematic in the typical etching process, may be prevented,thereby ensuring process stability and reliability.

Accordingly, this method may be efficiently applied to varioussemiconductor fabrication processes in which a nitride film is requiredto be selectively etched with respect to an oxide film.

FIG. 2A to FIG. 2C are cross-sectional views showing a device isolationprocess for a flash memory device in accordance with at least oneembodiment. Herein, the device isolation process may include an etchingprocess employing an etching composition (e.g., a high-selectivityetching composition) according to the present embodiments.

Referring to FIG. 2A, in at least one embodiment, tunnel oxide layer 21,polysilicon layer 22, buffer oxide layer 23 and/or pad nitride layer 24may be formed on substrate 20. For example, in some embodiments, tunneloxide layer 21, polysilicon layer 22, buffer oxide layer 23 and/or padnitride layer 24 may be sequentially formed on substrate 20.

Pad nitride layer 24, buffer oxide layer 23, polysilicon layer 22 and/ortunnel oxide layer 21 may be selectively etched by photolithography andetching processes to expose device isolation regions of substrate 20.Then, the exposed regions of substrate 20 may be selectively etchedusing pad nitride layer 24 as a mask to form at least one trench 25having a predetermined depth from a surface of substrate 20.

Referring to FIG. 2B, oxide layer 26 may be formed on an entire surfaceof substrate 20 so as to gap-fill at least one trench 25. For example,oxide layer 26 may be formed by a chemical vapor deposition (CVD).

A chemical mechanical polishing (CMP) process may be performed on oxidelayer 26 using pad nitride layer 24 as a polishing stop layer. Then, acleaning process may be performed using a dry etching.

Referring to FIG. 2C, pad nitride layer 24 may be selectively removed bya wet-etching process using an etching composition according to thepresent embodiment, and then buffer oxide layer 23 may be removed by acleaning process, thereby forming a device isolation layer 26A in afield region.

As shown in FIG. 2C, in at least one embodiment, a high-selectivityetching composition having a high etching selectivity for a nitridelayer with respect to an oxide layer may be used. When thehigh-selectivity etching composition is used, the nitride layer may beselectively removed for a sufficient time while the etching of the oxidelayer gap-filled in an STI pattern is minimized. In this case, suchselective removal of the nitride layer may be completely performed.Accordingly, in the present embodiments using the high-selectivityetching composition, an effective field oxide height (EFH) may be easilycontrolled. Furthermore, in the present embodiments using thehigh-selectivity etching composition, an electrical characteristicdeterioration and a particle generation caused by damage to an oxidelayer or etching of the oxide layer may be prevented, thereby improvingdevice characteristics.

As described above, a high-selectivity etching composition according tothe present embodiments may be applied to a device isolation process fora flash memory device, but is not limited thereto. For example, ahigh-selectivity etching composition according to the presentembodiments may be applied to a device isolation process for a DRAMdevice.

FIG. 3A to 3F are cross-sectional views showing a process of formingchannels for a flash memory device in accordance with at least oneembodiment. Herein, the channel forming process may include an etchingprocess employing an etching composition (e.g., a high-selectivityetching composition) according to the present embodiments.

Referring to FIG. 3A, in at least one embodiment, pipe gate electrodelayer 31 may be formed on substrate 30. In this case, nitride layer 32for forming a pipe channel may be buried in pipe gate electrode layer31. Herein, pipe gate electrode layer 31 includes first conductive layer31A and/or second conductive layer 31B. For example, at least one offirst conductive layer 31A and second conductive layer 31B may includean impurity-doped polysilicon.

More specifically, first conductive layer 31A is formed on substrate 30,and a nitride layer is deposited on first conductive layer 31A and ispatterned to form nitride layer 32 for forming at least one pipechannel. Subsequently, second conductive layer 31B is formed on firstconductive layer 31A exposed through nitride layer 32. First conductivelayer 31A and/or second conductive layer 31B form pipe gate electrodelayer 31.

In order to form a plurality of memory cells that are verticallystacked, at least one first interlayer insulating layer 33 and at leastone first gate electrode layer 34 may be alternately stacked as shown inFIG. 3A. Hereinafter, for the convenience of descriptions, thealternating stack structure of at least one first interlayer insulatinglayer 33 and at least one first gate electrode layer 34 will be referredto as “a cell gate structure (CGS).”

Herein, at least one first interlayer insulating layer 33 may serve toseparate memory cells through a plurality of layers. For example, in atleast one embodiment, at least one first interlayer insulating layer 33may comprise an oxide layer, and at least one first gate electrode layer34 may comprise an impurity-doped polysilicon. As shown in FIG. 3A, atleast one first interlayer insulating layer 33 and/or at least one firstgate electrode layer 34 are shown to consist of six layers, but are notlimited thereto.

The cell gate structure (CGS) may be selectively etched to form at leastone hole that exposes nitride layer 32. For example, the cell gatestructure (CGS) may be selectively etched to form a pair of first andsecond holes H1 and H2 that expose nitride layer 32. Herein, the firstand second holes H1 and H2 may be regions for forming channels formemory cells.

Referring to FIG. 3B, at least one nitride layer 35 which is buried inthe first and second holes H1 and H2 may be formed. In this case, atleast one nitride layer 35 may serve to prevent damages occurring in atrench formation process (described later in FIG. 3C) when at least onefirst gate electrode layer 34 is exposed through the first and secondholes H1 and H2.

Referring to FIG. 3C, in order to separate at least one first gateelectrode layer 34 into portions corresponding to each of the first andsecond holes H1 and H2, a trench “S” may be formed by selectivelyetching a cell gate structure (CGS) between a pair of the first andsecond holes H1 and H2.

Referring to FIG. 3D, sacrificial layer 36 which is buried in the trench“S” may be formed.

Referring to FIG. 3E, in at least one embodiment, for formation of aselection transistor, at least one second interlayer insulating layer 37and at least one second gate electrode layer 38 may be sequentiallyformed on the structure (e.g., a structure shown in FIG. 3D) resultingfrom the above process (e.g., a process described in connection withFIG. 3A to FIG. 3D). For example, as shown in FIG. 3E, a secondinterlayer insulating layer 37, a second gate electrode layer 38, andanother second interlayer insulating layer 37 may be sequentiallyformed. Hereinafter, for the convenience of descriptions, a stackstructure of at least one second interlayer insulating layer 37 and atleast one second gate electrode layer 38 will be referred to as “aselection gate structure (SGS).”

For example, in at least one embodiment, the at least one secondinterlayer insulating layer 37 may comprise an oxide layer, but is notlimited thereto. The at least one second gate electrode layer 38 maycomprise an impurity-doped polysilicon, but is not limited thereto.

The selection gate structure (SGS) may be selectively etched to form atleast one hole that exposes nitride layer 35 buried in a pair of thefirst and second holes H1 and H2. For example, the selection gatestructure (SGS) may be selectively etched to form third and fourth holesH3 and H4 that expose nitride layer 35 buried in a pair of the first andsecond holes H1 and H2. Herein, the third and fourth holes H3 and H4 maybe regions in which channels for selection transistors are to be formed.

Referring to FIG. 3F, (i) nitride layer 35 exposed through the third andfourth holes H3 and H4 and (ii) nitride layer 32 disposed below nitridelayer 35 may be selectively removed by a wet-etching process using anetching composition according to the present embodiments.

In the case that a process of forming channels for a flash memory(including an etching process) according to the present embodiments isperformed, at least one channel hole (e.g., a pair of channel holes H5and H6) for forming channel layers of memory cells may be formed.Furthermore, at least one pipe channel hole (e.g., H7) may be formedbelow the channel holes H5 and H6 such that the channel holes H5 and H6are connected to each other. In a process of forming channels for aflash memory (including an etching process) according to the presentembodiments, nitride layers may be selectively removed for a sufficienttime without loss of oxide layers by using a high-selectivity etchingcomposition, and thus the pipe channel(s) may be accurately formedwithout a profile loss. In this case, such selective removal of thenitride layers may be completely performed. In addition, in a process offorming channels for a flash memory (including an etching process)according to the present embodiments, a typical problem such as aparticle generation may be prevented, and thus the stability andreliability of the process may be ensured.

Then, such subsequent processes as a process of forming a floating gateand a process of forming a control gate may be performed, therebyforming a flash memory device.

FIGS. 4A and 4B are cross-sectional views illustrating a process offorming a diode for a phase-change memory device in accordance with atleast one embodiment. Herein, the diode forming process may include anetching process employing an etching composition (e.g., ahigh-selectivity etching composition) according to the presentembodiments.

Referring to FIG. 4A, in at least one embodiment, an insulatingstructure may be provided on substrate 40. Herein, the insulatingstructure may include holes exposing conductive region 41. For example,conductive region 41 may be an n⁺ impurity region, but is not limitedthereto.

Polysilicon layer 42 may be formed so as to fill portions of the holes,followed by ion implantation of impurities, thereby forming diodes.

Titanium silicide layer 43 may be formed on polysilicon layer 42. Forexample, titanium silicide layer 43 may be formed by forming a titaniumlayer and heat-treating the formed titanium layer so as to react withpolysilicon layer 42.

Titanium nitride layer 44 and nitride layer 45 may be sequentiallyformed on titanium silicide layer 43. For example, titanium nitridelayer 44 may be formed on titanium silicide layer 43, and then nitridelayer 45 may be formed on titanium nitride layer 44.

Oxide layer 46 may be formed in an isolated space between the diodeswhich are formed by performing a dry etching process using a hard mask.Then, a chemical mechanical polishing (CMP) process may be performed toform a primary structure of bottom electrodes isolated from each other.

Referring to FIG. 4B, nitride layer 45 may be selectively removed byperforming a wet-etching process on the structure (e.g., a structureshown in FIG. 4A) resulting from the above process described inconnection with FIG. 4A. Herein, the wet-etching process may beperformed using an etching composition (e.g., a high-selectivity etchingcomposition) according to the present embodiments. In at least oneembodiment, the high-selectivity etching composition may be used toremove a nitride layer. In this case, the nitride layer may beselectively removed for a sufficient time without loss of an oxidelayer. Such selective removal of the nitride layer may be completelyperformed. Furthermore, in the present embodiments using thehigh-selectivity etching composition, an electrical characteristicdeterioration and a particle generation caused by damage to an oxidelayer or etching of the oxide layer may be prevented, thereby improvingdevice characteristics. A titanium may be deposited in the spacesremaining after removal of nitride layer 45, thereby forming bottomelectrodes.

As described above, an etching process using a high-selectivity etchingcomposition according to the present embodiments may be applied to avariety of semiconductor device-fabricating methods. For example, suchetching process according to the present embodiments may be applied toprocesses in which selective removal of a nitride layer is required.More specifically, such etching process according to the presentembodiments may be applied to processes in which a nitride layer isrequired to be selectively etched from a structure in which nitridelayers and oxide layers are stacked alternately or present together.

Hereinafter, embodiments of the present disclosure will be described infurther detail with reference to examples and comparative examples. Itis to be understood, however, that these examples are illustrativepurposes and are not intended to limit the scope of the embodiments ofthe present disclosure.

First Embodiment A: Manufacturing Etching Composition

In the first embodiment A, an etching composition may be produced bymixing at least one of silane inorganic acid salts and phosphoric acidwith predetermined weight ratios as shown in Table 1A below. As a firstinorganic acid, a 85% aqueous solution is used.

TABLE 1A 1st IA Silane Inorganic Acid Salts (SIAS) PA Weight ratio PT wt% wt % Silane Compound (SC) 2nd IA (2nd IA:SC) (° C.) Example A1 85 1 SCexpressed by Phosphoric 20:100 70 Formula A1, wherein R¹ acid is methyland R² to R⁴ (PA) are chloro. Example A2 83 1 SC expressed by Phosphoric 5:100 90 Formula A1, wherein R¹ acid to R⁴ are ethoxyl. (PA) Example A384 1 SC expressed by Sulfuric acid 10:100 70 Formula A1, wherein R¹ (SA)is methyl and R² to R⁴ are chloro. Example A4 83 1 SC expressed bySulfuric acid 20:100 40 Formula A1 where R¹ to (SA) R⁴ are ethoxyl.Example A5 83 1 SC expressed by Nitric acid 10:100 50 Formula A1 whereR¹ is (NA) methyl and R² to R⁴ are chloro. Example A6 85 3 SC expressedby Nitric acid 10:100 40 Formula A1 where R¹ to (NA) R⁴ are ethoxyl. 1)1^(st) IA: first inorganic acid 2) 2^(nd) IA: second inorganic acid 3)PA: phosphoric acid

FIG. 5 is a graph showing nuclear magnetic resonance (NMR) data ofsilane inorganic acid salts produced according to the first embodimentA.

Referring to FIG. 5, the graph shows that at least one of silaneinorganic acid salts in an etching composition in accordance with atleast one embodiment. That is, a compound expressed by the Formula A1where R¹ is methyl and R² to R⁴ are chloro is reacted with phosphoricacid (e.g., the second inorganic acid). As a result, the at least one ofthe silane inorganic acid salts may be produced. That is, the graph ofFIG. 5 includes broad peaks at about 11.1364 ppm and about 11.4053 ppm,which are different from a sharp peak that indicates a single compound.Accordingly, such broad peaks indicate the etching composition includesa plurality of silane inorganic acid salts having various formulas.

Experimental Example A1: Measure Selectivity of Etching Composition

Using the etching composition of the present embodiment, etching for anitride layer and an oxide layer was carried out at a processtemperature of 157° C. Etch rate and selectivity for the nitride layerand the oxide layer were measured using an ellipsometer (NANO VIEW,SEMG-1000) that is a film thickness measurement system. The results ofthe measurement are shown in Table A2 below. The etch rate wasdetermined by etching each of the layers for about 300 seconds andmeasuring the difference between the thickness of each layer beforeetching and the layer thickness of each layer after etching. Thus, theetch rate is obtained by dividing the thickness difference by theetching time (minute). The etching selectivity is expressed as the ratioof the etch rate of the nitride layer to that of the oxide layer.

TABLE A2 Process Etch rate temperature (Å/min) of Etch rate (Å/min) ofoxide layer Selectivity (° C.) nitride layer ThO_(x) ¹⁾ LP-TEOS²⁾ BPSG³⁾LP-TEOS BPSG Example A1 157 58.24 0.30 0.21 0.76 277.33 76.63 Example A2157 58.73 0.26 0.18 1.08 326.28 54.38 Example A3 157 58.21 0.29 0.220.93 264.59 62.59 Example A4 157 58.27 0.70 0.11 0.89 529.73 65.47Example A5 157 58.91 0.30 0.122 0.86 482.87 68.50 Example A6 157 58.810.25 0.07 1.14 840.14 51.59 ¹⁾ThO: thermal oxide layer ²⁾LP-TEOS: LowPressure Tetra Ethyl Ortho Silicate layer ³⁾BPSG: Borophosphate SilicateGlass layer

Comparative Examples A1 to A3: Manufacturing Etching Composition

In Comparative Example A1, etching was carried out using phosphoric acidat a process temperature of 157° C. Etch rate and etching selectivitywere measured in the same manner as the above Examples. In ComparativeExample 2, etching was carried out using a mixture of 0.05% hydrofluoricacid and phosphoric acid mixed at a low temperature of 130° C. InComparative Example A3, etching was carried out using the same mixtureas that of Comparative Example A2 at a process temperature of 157° C. InComparative Examples A2 and A3, the etch rate and selectivity weremeasured in the same manner as the above Examples. The phosphoric acidused in Comparative Examples A1 to A3 was a 85% aqueous solution ofphosphoric acid. The results of measurement in Comparative Examples A1to A3 are shown in Table A3 below.

TABLE A3 Etch rate Process (Å/min) of Etching temp. nitride Etch rate(Å/min) of oxide layer Selectivity composition (° C.) layer ThOx LP-TEOSBPSG LP-TEOS BPSG Comp. Phosphoric 157 61.32 1.1 13.19 9.85 4.64 6.23Example acid A1 Comp. Phosphoric 130 15.44 0 2.3 1.03 6.71 14.99 Exampleacid + A2 Hydrofluoric acid (0.05 wt %) Comp. Phosphoric 157 76.12 5.6732.14 20.48 2.36 3.71 Example acid + A3 Hydrofluoric acid (0.05 wt %)

As can be seen in Table A2 and Table A3, the etching compositions showeda significantly high etching selectivity for the nitride layer withrespect to the oxide layer compared to those of Comparative Examples A1to A3. Thus, when the high-selectivity etching composition of thepresent embodiment is used, the EFH may be easily controlled bycontrolling the etch rate of the oxide layer, and damage to the oxidelayer may be prevented. In addition, particle generation, which wasproblematic, may be prevented, thus ensuring the stability andreliability of the etching process.

Experimental Example A2: Measuring Variation According to Time

The etching compositions produced in Examples A1 and A2 is mixed with aphosphoric acid. Etching for a nitride layer and an oxide layer wascarried out, using each of the mixtures, immediately after mixing (0hour) and at 8 hours after mixing. The etch rates and selectivity forthe nitride layer and the oxide layer were measured. In ComparativeExample 4 (base PA), the etch rate and selectivity for a nitride layerto and an oxide layer were evaluated using phosphoric acid in the samemanner as the above examples.

The evaluation was performed at a process temperature of 160° C. Theetch rate was determined by etching each of the layers for about 300seconds and measuring the difference between the thickness of each layerbefore etching and the layer thickness of the each layer after etching.Thus, the etch rate is obtained by dividing the thickness difference bythe etching time (minute). The etching selectivity is expressed as theratio of the etch rate of the nitride film to that of the PSZ film. Theevaluation results are shown in Table A4 below.

TABLE A4 Etch rate Etch rate (Å/min) Selectivity (Å/min) of of oxidelayer (nitride nitride layer PSZ¹⁾ BPSG layer/PSZ) Example A1 0 hr 58.240.67 0.76 86.92 After 8 hr 58.24 0.67 0.76 86.92 Example A2 0 hr 58.730.52 0.73 112.94 After 8 hr 58.73 0.52 0.73 112.94 Example A4 0 hr 60 1590 <4 After 8 hr 60 15 90 <4 ¹⁾PSZ: Polysilazane layer

As can be seen in Table A4, the etching compositions of the presentembodiment showed a very high etching selectivity for the nitride layercompared to a typical etching composition including phosphoric acid.Thus, when the high-selectivity etching composition of the presentembodiment is used to remove a nitride layer, the nitride layer may beselectively etched, while the deterioration in electricalcharacteristics caused by damage to the oxide layer or etching of theoxide layer may be prevented and particle generation may be prevented,which improves the device properties.

Second Embodiment B: Manufacturing an Etching Composition

In according to the second embodiment B, an etching composition ismanufactured by mixing silane inorganic acid salts with phosphoric acidat the weight ratios shown in Table B1 below. As a first inorganic acid,a 85% aqueous solution was used.

TABLE B1 1st IA Silane Inorganic Acid Salts (SIAS) PA Weight ratio PT wt% wt % Silane Compound (SC) 2nd IA (2nd IA:SC) (° C.) Example B1 85 1 SCexpressed by Pyrophosphoric 10:100 70 Formula A1, wherein R¹ acid ismethyl and R² to R⁴ are chloro. Example B2 85 1 SC expressed byPyrophosphoric 20:100 90 Formula A1, wherein R¹ acid to R⁴ are ethoxyl.Example B3 85 1 SC expressed by Polyphosphoric 20:100 70 Formula A1,wherein R¹ acid is methyl and R² to R⁴ are chloro. Example B4 85 1 SCexpressed by Polyphosphoric 20:100 90 Formula A1 where R¹ to acid R⁴ areethoxyl. 1) 1^(st) IA: first inorganic acid 2) 2^(nd) IA: secondinorganic acid 3) PT: Process temperature

Experimental Example B1: Measuring Selectivity of Etching Composition

Using the etching composition of the second embodiment B1, etching for anitride layer and an oxide layer was carried out at a processtemperature of 157° C. Etch rate and selectivity for the nitride layerand the oxide layer were measured using an ellipsometer (NANO VIEW,SEMG-1000) that is a film thickness measurement system. The results ofthe measurement are shown in Table B2 below. The etch rate wasdetermined by etching each of the layers for about 300 seconds andmeasuring the difference between the thickness of each layer beforeetching and the layer thickness of each layer after etching. Thus, theetch rate is obtained by dividing the thickness difference by theetching time (minute). The etching selectivity is expressed as the ratioof the etch rate of the nitride layer to that of the oxide layer.

TABLE B2 Process Etch rate temperature (Å/min) of Etch rate (Å/min) ofoxide layer Selectivity (° C.) nitride layer ThO_(x) ¹⁾ LP-TEOS²⁾ BPSG³⁾LP-TEOS BPSG Example B1 157 58.63 0.24 0.20 0.71 293.15 82.58 Example B2157 58.65 0.21 0.25 0.75 234.60 78.20 Example B3 157 58.57 0.25 0.150.71 390.47 82.49 Example B4 157 58.31 0.23 0.17 0.81 343.00 71.99¹⁾ThO: thermal oxide layer ²⁾LP-TEOS: Low Pressure Tetra Ethyl OrthoSilicate layer ³⁾BPSG: Borophosphate Silicate Glass layer

Comparative Examples B1 to B3: Producing an Etching Composition

In Comparative Example B1, etching was carried out using phosphoric acidat a process temperature of 157° C. Etch rate and etching selectivitywere measured in the same manner as the above Examples. In ComparativeExample B2, etching was carried out using a mixture of 0.05%hydrofluoric acid and phosphoric acid mixed at a low temperature of 130°C. Etch rate and etching selectivity were measured in the same manner asthe above Examples. In Comparative Example B3, etching was carried outusing the same mixture as that of Comparative Example B2 at a processtemperature of 157° C. Etch rate and etching selectivity were measuredin the same manner as the above Examples. The phosphoric acid used inComparative Examples B1 to B3 was a 85% aqueous solution of phosphoricacid. The results of measurement in Comparative Examples B1 to B3 areshown in Table B3 below.

TABLE B3 Etch rate Process (Å/min) of Etching temp. nitride Etch rate(Å/min) of oxide layer Selectivity composition (° C.) layer ThOx LP-TEOSBPSG LP-TEOS BPSG Comp. Phosphoric 157 61.32 1.1 13.19 9.85 4.64 6.23Example acid B1 Comp. Phosphoric 130 15.44 0 2.3 1.03 6.71 14.99 Exampleacid + B2 Hydrofluoric acid (0.05 wt %) Comp. Phosphoric 157 76.12 5.6732.14 20.48 2.36 3.71 Example acid + B3 Hydrofluoric acid (0.05 wt %)

As can be seen in Table B2 and Table B3, the etching compositions showeda significantly high etching selectivity for the nitride layer withrespect to the oxide layer compared to those of Comparative Examples B1to B3. Thus, when the high-selectivity etching composition of thepresent embodiment is used, the EFH may be easily controlled bycontrolling the etch rate of the oxide layer, and damage to the oxidelayer may be prevented. In addition, particle generation, which wasproblematic, may be prevented, thus ensuring the stability andreliability of the etching process.

Third Embodiment C: Manufacturing Etching Composition

In accordance with the third embodiment C, an etching composition ismanufactured by mixing siloxane inorganic acid salts with phosphoricacid at the weight ratios shown in Table C1 below. As a first inorganicacid, a 85% aqueous solution was used.

TABLE C1 1st IA Siloxane Inorganic Acid Salts PA Siloxane CompoundWeight ratio PT wt % wt % (SxC) 2nd IA (2nd IA:SC) (° C.) Example C1 852 SxC expressed by Phosphoric 50:100 90 Formula A2, wherein R⁶ acid toR⁹ are chloro, R⁵ and (PA) R¹⁰ are methyl, and n is 1. Example C2 83 4SxC expressed by Pyrophosphoric 50:100 90 Formula A2, wherein R⁶ acid toR⁹ are chloro, R⁵ and (PA) R¹⁰ are methyl, and n is 1. Example C3 84 3SxC expressed by Sulfuric acid 40:100 120 Formula A2, wherein R⁶ (SA) toR⁹ are chloro, R⁵ and R¹⁰ are methyl, and n is 1. Example C4 83 5 SxCexpressed by Nitric acid 50:100 150 Formula A2, wherein R⁶ (NA) to R⁹are chloro, R⁵ and R¹⁰ are methyl, and n is 1. Example C5 83 5 SxCexpressed by Polyphosphoric 50:100 150 Formula A2, wherein R⁶ acid to R⁹are chloro, R⁵ and (containing R¹⁰ are methyl, and n is three 1.phosphoric atoms) 1^(st) IA: first inorganic acid 2^(nd) IA: secondinorganic acid PT: process temperature

Experimental Example C1: Measuring Selectivity of Produced EtchingComposition

Using the etching composition of the third embodiment C1, etching for anitride layer and an oxide layer was carried out at a processtemperature of 157° C. Etch rate and selectivity for the nitride layerand the oxide layer were measured using an ellipsometer (NANO VIEW,SEMG-1000) that is a film thickness measurement system. The results ofthe measurement are shown in Table B2 below. The etch rate wasdetermined by etching each of the layers for about 300 seconds andmeasuring the difference between the thickness of each layer beforeetching and the layer thickness of each layer after etching. Thus, theetch rate is obtained by dividing the thickness difference by theetching time (minute). The etching selectivity is expressed as the ratioof the etch rate of the nitride layer to that of the oxide layer.

TABLE C2 Process Etch rate temperature (Å/min) of Etch rate (Å/min) ofoxide layer Selectivity (° C.) nitride layer ThO_(x) ¹⁾ LP-TEOS²⁾ BPSG³⁾LP-TEOS BPSG Example C1 157 58.16 0.33 0.27 0.75 215.41 77.55 Example C2157 58.43 0.35 0.24 0.80 243.46 73.04 Example C3 157 58.75 0.35 0.280.75 209.82 78.33 Example C4 157 58.35 0.35 0.24 0.78 243.13 74.81¹⁾ThO: thermal oxide layer ²⁾LP-TEOS: Low Pressure Tetra Ethyl OrthoSilicate layer ³⁾BPSG: Borophosphate Silicate Glass layer

Comparative Examples C1 to C3: Producing an Etching Composition

In Comparative Example C1, etching was carried out using phosphoric acidat a process temperature of 157° C. Etch rate and etching selectivitywere measured in the same manner as the above Examples. In ComparativeExample C2, etching was carried out using a mixture of 0.05%hydrofluoric acid and phosphoric acid mixed at a low temperature of 130°C. Etch rate and etching selectivity were measured in the same manner asthe above Examples. In Comparative Example C3, etching was carried outusing the same mixture as that of Comparative Example C2 at a processtemperature of 157° C. Etch rate and etching selectivity were measuredin the same manner as the above Examples. The phosphoric acid used inComparative Examples C1 to C3 was a 85% aqueous solution of phosphoricacid. The results of measurement in Comparative Examples C1 to C3 areshown in Table C3 below.

TABLE C3 Etch rate Process (Å/min) of Etching temp. nitride Etch rate(Å/min) of oxide layer Selectivity composition (° C.) layer ThOx LP-TEOSBPSG LP-TEOS BPSG Comp. Phosphoric 157 61.32 1.1 13.19 9.85 4.64 6.23Example acid C1 Comp. Phosphoric 130 15.44 0 2.3 1.03 6.71 14.99 Exampleacid + C2 Hydrofluoric acid (0.05 wt %) Comp. Phosphoric 157 76.12 5.6732.14 20.48 2.36 3.71 Example acid + C3 Hydrofluoric acid (0.05 wt %)

As can be seen in Table C2 and Table C3, the etching compositions showeda significantly high etching selectivity for the nitride layer withrespect to the oxide layer compared to those of Comparative Examples C1to C3. Thus, when the high-selectivity etching composition of thepresent embodiment is used, the EFH may be easily controlled bycontrolling the etch rate of the oxide layer, and damage to the oxidelayer may be prevented. In addition, particle generation, which wasproblematic, may be prevented, thus ensuring the stability andreliability of the etching process.

Experimental Example C2: Measuring Variation According to Time

Using the etching compositions produced in the Examples C1, etching fora nitride layer and an oxide layer was carried out immediately aftermixing (0 hour) with phosphoric acid and at 8 hours after mixing withphosphoric acid. The etch rates and selectivity for the nitride layerand the oxide layer were measured. In Comparative Example C4, the etchrate and selectivity for a nitride layer and an oxide layer wereevaluated using phosphoric acid in the same manner as the aboveexamples.

The evaluation was performed at a process temperature of 160° C. Theetch rate was determined by etching each of the layers for about 300seconds and measuring the difference between the thickness of each layerbefore etching and the layer thickness of the each layer after etching.Thus, the etch rate is obtained by dividing the thickness difference bythe etching time (minute). The etching selectivity is expressed as theratio of the etch rate of the nitride film to that of the PSZ film. Theevaluation results are shown in Table C4 below.

TABLE C4 Etch rate Etch rate (Å/min) Selectivity (Å/min) of of oxidelayer (nitride nitride layer PSZ¹⁾ BPSG layer/PSZ) Example C1 0 hr 58.240.50 0.73 116.92 After 8 hr 58.24 0.50 0.73 116.92 Example C4 0 hr 60 1590 <4 After 8 hr 60 15 90 <4 ¹⁾PSZ: Polysilazane layer

As can be seen in Table C4, the etching compositions of the example C1showed a very high etching selectivity for the nitride layer compared toa typical etching composition including phosphoric acid. Thus, when thehigh-selectivity etching composition of the present embodiment is usedto remove a nitride layer, the nitride layer may be selectively etched,while the deterioration in electrical characteristics caused by damageto the oxide layer or etching of the oxide layer may be prevented andparticle generation may be prevented, which improves the deviceproperties.

Fourth Embodiment D: Manufacturing Etching Composition

In accordance with the fourth embodiment D, an etching composition ismanufactured by mixing silane inorganic acid salts with phosphoric acidat the weight ratios shown in Table D1 below. As the phosphoric acid, a85% aqueous solution was used.

TABLE D1 1st IA First Silane Silane Inorganic Acid Salts (SIAS) PACompound (1^(st) SC) Second Silane Weight ratio PT wt % wt % wt %Compound (2^(nd) SC) 2nd IA (2nd IA:SC) (° C.) Exam. 85 1^(st) SCexpressed 2 2^(nd) SC expressed by Phosphoric 20:100 90 D1 by FormulaA1, Formula A1, wherein acid wherein R¹ is R¹ is methyl and R² (PA)methyl and R² to to R⁴ are chloro. R⁴ are chloro. (1) Exam. 85 1^(st) SCexpressed 2 2^(nd) SC expressed by Phosphoric 20:100 120 D2 by FormulaA1, Formula A1, wherein acid wherein R¹ to R⁴ R¹ to R⁴ are ethoxyl. (PA)are ethoxyl. (1) Exam. 85 1^(st) SC expressed 1 2^(nd) SC expressed byPhosphoric 50:100 90 D3 by Formula A2, Formula A2 wherein acid whereinR⁶ to R⁹ R⁶ to R⁹ are chloro, (PA) are chloro, R⁵ and R⁵ and R¹⁰ are R¹⁰are methyl, methyl, and n is 1. and n is 1. (1) Exam. 85 1^(st) SCexpressed 3 2^(nd) SC expressed by Sulfuric acid 20:100 90 D4 by FormulaA1, Formula A1, wherein (SA) wherein R¹ is R¹ is methyl and R² methyland R² to to R⁴ are chloro. R⁴ are chloro. (2) Exam. 85 1^(st) SCexpressed 2 2^(nd) SC expressed by Nitric acid 10:100 120 D5 by FormulaA1, Formula A1 where R¹ (NA) wherein R¹ is is methyl and R² to methyland R² to R⁴ are chloro. R⁴ are chloro. (1)

Experimental Example D1: Measure Selectivity of Produced EtchingComposition

Using the produced etching composition of the fourth embodiment, etchingfor a nitride layer and an oxide layer was carried out at a processtemperature of 157° C. Etch rate and selectivity for the nitride layerand the oxide layer were measured using an ellipsometer (NANO VIEW,SEMG-1000) that is a film thickness measurement system. The results ofthe measurement are shown in Table D2 below. The etch rate wasdetermined by etching each of the layers for about 300 seconds andmeasuring the difference between the thickness of each layer beforeetching and the layer thickness of each layer after etching. Thus, theetch rate is obtained by dividing the thickness difference by theetching time (minute). The etching selectivity is expressed as the ratioof the etch rate of the nitride layer to that of the oxide layer.

TABLE D2 Process Etch rate temperature (Å/min) of Etch rate (Å/min) ofoxide layer Selectivity (° C.) nitride layer ThO_(x) ¹⁾ LP-TEOS²⁾ BPSG³⁾LP-TEOS BPSG Example D1 157 58.3 0.31 0.31 0.73 188.06 79.86 Example D2157 58.6 0.32 0.32 0.73 183.13 80.27 ¹⁾ThO: thermal oxide layer²⁾LP-TEOS: Low Pressure Tetra Ethyl Ortho Silicate layer ³⁾BPSG:Borophosphate Silicate Glass layer

Comparative Examples D1 to D3: Producing Etching Composition

In Comparative Example D1, etching was carried out using phosphoric acidat a process temperature of 157° C. Etch rate and etching selectivitywere measured in the same manner as the above Examples. In ComparativeExample D2, etching was carried out using a mixture of 0.05%hydrofluoric acid and phosphoric acid mixed at a low temperature of 130°C. In Comparative Example D3, etching was carried out using the samemixture as that of Comparative Example D2 at a process temperature of157° C. In Comparative Examples D2 and D3, the etch rate and selectivitywere measured in the same manner as the above Examples. The phosphoricacid used in Comparative Examples D1 to D3 was a 85% aqueous solution ofphosphoric acid. The results of measurement in Comparative Examples D1to D3 are shown in Table D3 below.

TABLE D3 Etch rate Process (Å/min) of Etching temp. nitride Etch rate(Å/min) of oxide layer Selectivity composition (° C.) layer ThOx LP-TEOSBPSG LP-TEOS BPSG Comp. Phosphoric 157 61.32 1.1 13.19 9.85 4.64 6.23Example acid D1 Comp. Phosphoric 130 15.44 0 2.3 1.03 6.71 14.99 Exampleacid + D2 Hydrofluoric acid (0.05 wt %) Comp. Phosphoric 157 76.12 5.6732.14 20.48 2.36 3.71 Example acid + D3 Hydrofluoric acid (0.05 wt %)

As can be seen in Table D2 and Table D3, the etching compositions showeda significantly high etching selectivity for the nitride layer withrespect to the oxide layer compared to those of Comparative Examples A1to A3. Thus, when the high-selectivity etching composition of thepresent embodiment is used, the EFH may be easily controlled bycontrolling the etch rate of the oxide layer, and damage to the oxidelayer may be prevented. In addition, particle generation, which wasproblematic, may be prevented, thus ensuring the stability andreliability of the etching process.

Reference herein to “one embodiment” or “an embodiment” means that aparticular feature, structure, or characteristic described in connectionwith the embodiment can be included in at least one embodiment of theinvention. The appearances of the phrase “in one embodiment” in variousplaces in the specification are not necessarily all referring to thesame embodiment, nor are separate or alternative embodiments necessarilymutually exclusive of other embodiments. The same applies to the term“implementation.”

As used in this application, the word “exemplary” is used herein to meanserving as an example, instance, or illustration. Any aspect or designdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects or designs. Rather, use ofthe word exemplary is intended to present concepts in a concretefashion.

Additionally, the term “or” is intended to mean an inclusive “or” ratherthan an exclusive “or”. That is, unless specified otherwise, or clearfrom context, “X employs A or B” is intended to mean any of the naturalinclusive permutations. That is, if X employs A; X employs B; or Xemploys both A and B, then “X employs A or B” is satisfied under any ofthe foregoing instances. In addition, the articles “a” and “an” as usedin this application and the appended claims should generally beconstrued to mean “one or more” unless specified otherwise or clear fromcontext to be directed to a singular form.

Moreover, the terms “system,” “component,” “module,” “interface,”,“model” or the like are generally intended to refer to acomputer-related entity, either hardware, a combination of hardware andsoftware, software, or software in execution. For example, a componentmay be, but is not limited to being, a process running on a processor, aprocessor, an object, an executable, a thread of execution, a program,and/or a computer. By way of illustration, both an application runningon a controller and the controller can be a component. One or morecomponents may reside within a process and/or thread of execution and acomponent may be localized on one computer and/or distributed betweentwo or more computers.

The present invention can be embodied in the form of methods andapparatuses for practicing those methods. The present invention can alsobe embodied in the form of program code embodied in tangible media,non-transitory media, such as magnetic recording media, opticalrecording media, solid state memory, floppy diskettes, CD-ROMs, harddrives, or any other machine-readable storage medium, wherein, when theprogram code is loaded into and executed by a machine, such as acomputer, the machine becomes an apparatus for practicing the invention.The present invention can also be embodied in the form of program code,for example, whether stored in a storage medium, loaded into and/orexecuted by a machine, or transmitted over some transmission medium orcarrier, such as over electrical wiring or cabling, through fiberoptics, or via electromagnetic radiation, wherein, when the program codeis loaded into and executed by a machine, such as a computer, themachine becomes an apparatus for practicing the invention. Whenimplemented on a general-purpose processor, the program code segmentscombine with the processor to provide a unique device that operatesanalogously to specific logic circuits. The present invention can alsobe embodied in the form of a bitstream or other sequence of signalvalues electrically or optically transmitted through a medium, storedmagnetic-field variations in a magnetic recording medium, etc.,generated using a method and/or an apparatus of the present invention.

It should be understood that the steps of the exemplary methods setforth herein are not necessarily required to be performed in the orderdescribed, and the order of the steps of such methods should beunderstood to be merely exemplary. Likewise, additional steps may beincluded in such methods, and certain steps may be omitted or combined,in methods consistent with various embodiments of the present invention.

As used herein in reference to an element and a standard, the term“compatible” means that the element communicates with other elements ina manner wholly or partially specified by the standard, and would berecognized by other elements as sufficiently capable of communicatingwith the other elements in the manner specified by the standard. Thecompatible element does not need to operate internally in a mannerspecified by the standard.

No claim element herein is to be construed under the provisions of 35U.S.C. § 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for” or “step for.”

Although embodiments of the present invention have been describedherein, it should be understood that the foregoing embodiments andadvantages are merely examples and are not to be construed as limitingthe present invention or the scope of the claims. Numerous othermodifications and embodiments can be devised by those skilled in the artthat will fall within the spirit and scope of the principles of thisdisclosure, and the present teaching can also be readily applied toother types of apparatuses. More particularly, various variations andmodifications are possible in the component parts and/or arrangements ofthe subject combination arrangement within the scope of the disclosure,the drawings and the appended claims. In addition to variations andmodifications in the component parts and/or arrangements, alternativeuses will also be apparent to those skilled in the art.

What is claimed is:
 1. A method of fabricating a semiconductor device,the method comprising an etching process that is carried out using anetching composition that selectively etches a nitride layer with respectto an oxide layer, wherein the etching composition includes: a firstinorganic acid; at least one of silane inorganic acid salts produced byreaction between a second inorganic acid and a silane compound; and asolvent, wherein: the second inorganic acid is at least one selectedfrom the group consisting of a sulfuric acid, a fuming sulfuric acid, anitric acid, a phosphoric acid, an anhydrous phosphoric acid, and acombination thereof; and the silane compound is a compound representedby a first formula:

where each one of R¹ to R⁴ is selected from the group consisting ofhydrogen, halogen, (C₁-C₁₀) alkyl, (C₁-C₁₀) alkoxy, and (C₆-C₃₀) aryl,and at least one of R¹ to R⁴ is one of halogen or (C₁-C₁₀) alkyl, andwherein the composition comprises about 0.01 to about 15 wt % of the atleast one of silane inorganic acid salts, about 70 to about 99 wt % ofthe first inorganic acid, and the solvent comprising the remainingbalance of the wt % of the composition.